1. Field of the Invention
This invention relates to low head hydropower facilities, and more particularly to a moveable element and power generation system for low head facilities.
2. Description of Related Art
Of the approximately 80,000 dams in the United States, about 2,500 of them produce some electricity. There is, therefore, a large inventory of non-hydropower producing dams. At these dams, water is released either continuously, or on an intermittent to regular basis for, among other things, flood control or irrigation purposes. Usually, governments and municipalities do not want anything to interfere with releasing water from the dams or reservoirs, or interfere with water movement downstream. Accordingly, anything fixed in the flow path of the water that might interfere with downstream water movement is undesirable to them. Previous solutions to increasing gross head pressure, which increases the potential for power generation, have involved moveable walls or flashboards that are deployed on the top of an existing dam structure to increase the gross head on a temporary basis.
Wicket-type gates have been utilized for navigation dams for over 100 years. These gates are often considered for navigable dam spillways, but they also function as non-navigable spillways. The gates can be lifted into position with a hydraulic or pneumatic cylinder applying force to the downstream side or with a gearbox. The wickets are generally held in an up position with a prop or strut that slides in a track on the lower pool side of the wicket. This allows the cylinder piston to be retracted, or extended during operating cycles.
These systems, however, are not intended for power generation, but to increase the height of the blocked water in the upper pool, thereby creating a larger gross head pressure. In some cases, the top of the existing dam is raised by these temporary walls and existing turbines positioned at the base of the dam receive increased head pressure which results in higher power production than without the higher gross head. However, none of these systems allow for the situational use of hydropower in a deployable system that may be placed in virtually any environment where low head is available while at the same time having the ability to let water pass over the turbine powerhouse during flooding events so that the turbine powerhouse does not reduce the flow of flood waters on the dam or dam spillway. Nor do any of these systems allow for a variety of combinations of turbines and movable walls to create interchangeable power generating cells and enhancements.